The present invention relates to compositions and, in particular, antireflective coating compositions for use in microelectronic application In a preferred aspect, compositions of the invention comprise 1) one or more glycidyl groups; and 2) one or more aromatic groups that each comprises two or more substituents that comprise hydroxy, thiol and/or amine moieties. Preferred compositions of the invention are used with an overcoated photoresist composition and may be referred to as bottom antireflective compositions or “BARCs”.
Photoresists are photosensitive films used for the transfer of images to a substrate. A coating layer of a photoresist is formed on a substrate and the photoresist layer is then exposed through a photomask to a source of activating radiation. Following exposure, the photoresist is developed to provide a relief image that permits selective processing of a substrate.
Reflection of activating radiation used to expose a photoresist often poses limits on resolution of the image patterned in the photoresist layer. Reflection of radiation from the substrate/photoresist interface can produce spatial variations in the radiation intensity in the photoresist, resulting in non-uniform photoresist linewidth upon development. Radiation also can scatter from the substrate/photoresist interface into regions of the photoresist where exposure is non-intended, again resulting in linewidth variations.
One approach used to reduce the problem of reflected radiation has been the use of a radiation absorbing layer (antireflective composition layer) interposed between the substrate surface and the photoresist coating layer. See U.S. Pat. Nos. 8,338,078; 6,927,0152; 5,677,112; 8,481,247; 8,012,670; 6,818,381; and 7,846,638; WO067329A1; and EP2000852.
SiO2, TiN and other metals are common substrates on which photoresist and antireflective compositions are coated. Silicon oxynitride (SiON) layers and other inorganics such as Si3N4 coatings have been employed in semiconductor device manufacture, for example as an etch stop layer and an inorganic antireflective layer. See U.S. Pat. Nos. 6,124,217; 6,153,504; and 6,245,682.
Dry etching is a frequently preferred of pattern transfer with a photoresist relief image. The plasma used however in a dry etch process can cause damage to thin oxide and nitride layers, such as may be employed in flash memory fabrication. As a consequence, wet etching is often used for pattern transfer trough such more fragile substrates due to relatively milder condition of wet etch processes.
Wet etching of metal nitrides, such as titanium nitride (TiN), has been carried out using either an aqueous mixture of ammonium hydroxide and hydrogen peroxide, or a mixture of an acid such as sulfuric acid and a peroxide such as hydrogen peroxide. See, for instance, US 2006/0226122.
A problem with such using conventional wet etchants is their lack of selectivity. These wet etchants often attack surrounding structures, resulting in either etching or, particularly in the case of some photoresists, swelling and/or loss of adhesion to substrates to which the photoresist is applied. Such lack of selectivity becomes increasingly less acceptable as critical dimensions continue to be reduced.
It thus would be desirable to have new antireflective compositions for use with an overcoated photoresist. It would be particularly desirable to have new antireflective compositions that exhibit enhanced performance and could provide increased resolution of an image patterned into an overcoated photoresist. It also would be desirable to have new antireflective compositions for application onto metal substrate surfaces and that would provide good resolution and metal substrate adherence including through a wet etching process.